1. Field of the Invention
The present invention relates to a seat frame for an automotive seat and, more particulary, to the reinforced structure of such seat frame.
2. Description of the Prior Art
Generally, as shown in FIG. 1, a seat S includes a seat frame (1) internally thereof which is formed of a rigid body such as metal or the like. That is, the seat S comprises the seat frame (1), a resilient member enclosing the periphery of the seat frame (1), and a trim cover assembly covering the surface thereof.
Conventionally, as such seat frame, there has been frequently used a seat frame which is formed as follows: that is, four frame materials each having a U-shaped section, namely, comprising a web and two upper and lower flanges projecting in the same direction relative to the web are connected to one another in a quadrilateral form with the flanges thereof facing internally. In this seat frame, when a lifter mechanism is equipped internally thereof, the lower flanges come into interference with the link means or leg means of the lifter mechanism. For this reason, there are formed holes or notches in the flanges, so that the link or leg means of the lifter mechanism can be faced to the lower side of the seat frame by means of such holes or notches.
Also, in a pan-type seat frame (1) as shown in FIGS. 2 and 3, when it is equipped with a lifter mechanism, two frame members of an L-shaped section are respectively attached to the two sides of the lower portion of the seat frame (1), and the link members (4)(5) of the lifter mechanism are connected to the vertical portions of the frame members (2), (see FIG. 2). On the other hand, when no lifter mechanism is provided, leg members (7) are fixedly secured to the lower portions of the two sides of the seat frame (1), so that the seat frame (1) can be attached via these leg members (7) to floor-side members such as slide rails and the like, (see FIG. 3).
In addition, such pan-type seat frame (1) is diadvantageous in strength, and, therefore, the side portions thereof are reinforced, especially the side surface thereof to which a reclining device is mounted is reinforced by a reinforcing member (8).
As described above, in the prior art, the seat frame formed of the frame materials each having a U-shaped section must be formed in the flange portions thereof with the holes or notches for prevention of interference with the lifter mechanism or the like, with the result that the seat frame is decreased in strength and involves a complicated manufacturing process which lowers the productivity thereof. This type of seat frame is also poor in a working efficiency due to the fact that, when it is directly fixed to the floor-side members such as the slide rails or the like, its upper flange stands in the way. Also, the pan-type seat frame requires another member for reinforcing or mounting, which increases the number of parts. As a result of this, the seat frame is disadvantageous in that it is heavy in weight and expensive.